In some conventional aeration systems, gas is compressed and pumped into tubes or diffusion devices for introduction into a fluid medium. In other conventional aeration systems, water is sprayed through gas to allow gas transfer before returning to a body of fluid to be aerated. These systems require large expenditures of mechanical energy, and further produce a localized or confined area of aeration. Such aeration areas then rapidly return to the surface of the fluid medium, or are confined to the momentary exposure to gas before contact with the fluid medium surface. Yet other aeration systems allow for gas to be entrained in an existing flow of fluid medium, but are limited to low efficiency pumps and are subject to fouling if used in high-particulate environments such as wastewater or sewage treatment plants.
Since efficient aeration of a fluid medium is a product of the surface diffusion interface between the interior of gas bubbles and the fluid medium, it is advantageous to increase this gas transfer potential by decreasing the relative size of gas bubbles and increasing their relative density. Since this process continues over time, it is also advantageous to keep introduced gas bubbles from reaching the surface of the fluid medium to the effect that a given quantity of gas is largely stripped of oxygen by the time it exits the fluid medium. It is also known that cooler water can contain a larger percentage of dissolved oxygen than warmer water, so there is an additional advantage to any cooling or refrigeration of the fluid-gas interface during the diffusion process.
An aeration system that can achieve a high rate of aeration while minimizing the disadvantages of conventional aeration systems is therefore desired.